The present invention relates to administering electrical signals to local areas of living tissue and monitoring conditions in such tissue. In particular, the present invention relates to a low-power modular circuit for controlling one or more electrodes that can be used to administer or monitor such electrical signals.
Electrodes for administering electrical signals or for monitoring electrical signals at specific locations in living tissue, such as the heart, are important tools used in many medical treatment or diagnosis. U.S. Pat. No. 6,473,653, entitled “Selective Activation of Electrodes within an Implantable Lead,” to Schallhorn et al., filed on Mar. 2, 2000, discloses an implantable multi-electrode lead adapted to allow selective activation of the included electrodes to electrically excite the tissue in the vicinities of the activated electrodes. U.S. Pat. No. 5,593,430, entitled “Bus System for Interconnecting an Implantable Medical Device with a Plurality of Sensors,” to Renger, filed on Jan. 27, 1995, discloses a two-conductor bus system for connecting physiologic sensors to a pacemaker. The two-conductor bus provides power to the sensors, and the sensors' output signals are modulated on the two wires.